scholarly journals Competitive binding of Rab21 and p120RasGAP to integrins regulates receptor traffic and migration

2011 ◽  
Vol 194 (2) ◽  
pp. 291-306 ◽  
Author(s):  
Anja Mai ◽  
Stefan Veltel ◽  
Teijo Pellinen ◽  
Artur Padzik ◽  
Eleanor Coffey ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Motility ◽  
Molecular Mechanisms ◽  
Regulatory Mechanism ◽  
Competitive Binding ◽  
Small Gtpase ◽  
Rab Gtpases ◽  
Endocytic Machinery ◽  
And Migration ◽  
Α Subunits

Integrin trafficking from and to the plasma membrane controls many aspects of cell behavior including cell motility, invasion, and cytokinesis. Recruitment of integrin cargo to the endocytic machinery is regulated by the small GTPase Rab21, but the detailed molecular mechanisms underlying integrin cargo recruitment are yet unknown. Here we identify an important role for p120RasGAP (RASA1) in the recycling of endocytosed α/β1-integrin heterodimers to the plasma membrane. Silencing of p120RasGAP attenuated integrin recycling and augmented cell motility. Mechanistically, p120RasGAP interacted with the cytoplasmic domain of integrin α-subunits via its GAP domain and competed with Rab21 for binding to endocytosed integrins. This in turn facilitated exit of the integrin from Rab21- and EEA1-positive endosomes to drive recycling. Our results assign an unexpected role for p120RasGAP in the regulation of integrin traffic in cancer cells and reveal a new concept of competitive binding of Rab GTPases and GAP proteins to receptors as a regulatory mechanism in trafficking.

scholarly journals Phospholipase D Activity Regulates Integrin-mediated Cell Spreading and Migration by Inducing GTP-Rac Translocation to the Plasma Membrane

2008 ◽  
Vol 19 (7) ◽  
pp. 3111-3123 ◽  
Author(s):  
Young Chan Chae ◽  
Jung Hwan Kim ◽  
Kyung Lock Kim ◽  
Hyun Wook Kim ◽  
Hye Young Lee ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Phospholipase D ◽  
Molecular Mechanisms ◽  
Direct Interaction ◽  
Cell Spreading ◽  
Small Gtpase ◽  
General Mechanism ◽  
Downstream Target ◽  
P21 Activated Kinase ◽  
And Migration

Small GTPase Rac is a crucial regulator of actin cytoskeletal rearrangement, and it plays an important role in cell spreading, migration, mitogenesis, phagocytosis, superoxide generation, and axonal growth. It is generally accepted that Rac activity is regulated by the guanosine triphosphate (GTP)/guanosine diphosphate (GDP) cycle. But, it is suggested that in addition to Rac-GTP loading, membrane localization is required for the initiation of downstream effector signaling. However, the molecular mechanisms that control the targeting of GTP-Rac to the plasma membrane remain largely unknown. Here, we have uncovered a signaling pathway linking phospholipase D (PLD) to the localized functions of Rac1. We show that PLD product phosphatidic acid (PA) acts as a membrane anchor of Rac1. The C-terminal polybasic motif of Rac1 is responsible for direct interaction with PA, and Rac1 mutated in this region is incapable of translocating to the plasma membrane and of activating downstream target p21-activated kinase upon integrin activation. Finally, we show that PA induces dissociation of Rho-guanine nucleotide dissociation inhibitor from Rac1 and that PA-mediated Rac1 localization is important for integrin-mediated lamellipodia formation, cell spreading, and migration. These results provide a novel molecular mechanism for the GTP-Rac1 localization through the elevating PLD activity, and they suggest a general mechanism for diverse cellular functions that is required localized Rac activation.

scholarly journals Mitotic Centromere-Associated Kinesin (MCAK/KIF2C) Regulates Cell Migration and Invasion by Modulating Microtubule Dynamics and Focal Adhesion Turnover

Cancers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 5673
Author(s):  
Ha Hyung Moon ◽  
Nina-Naomi Kreis ◽  
Alexandra Friemel ◽  
Susanne Roth ◽  
Dorothea Schulte ◽  
...  
Keyword(s):  
Cell Motility ◽  
Molecular Mechanisms ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Focal Adhesions ◽  
Protein Composition ◽  
Cell Types ◽  
Migration And Invasion ◽  
And Migration ◽  
Cytoskeleton Dynamics

The microtubule (MT) cytoskeleton is crucial for cell motility and migration by regulating multiple cellular activities such as transport and endocytosis of key components of focal adhesions (FA). The kinesin-13 family is important in the regulation of MT dynamics and the best characterized member of this family is the mitotic centromere-associated kinesin (MCAK/KIF2C). Interestingly, its overexpression has been reported to be related to increased metastasis in various tumor entities. Moreover, MCAK is involved in the migration and invasion behavior of various cell types. However, the precise molecular mechanisms were not completely clarified. To address these issues, we generated CRISPR/dCas9 HeLa and retinal pigment epithelium (RPE) cell lines overexpressing or downregulating MCAK. Both up- or downregulation of MCAK led to reduced cell motility and poor migration in malignant as well as benign cells. Specifically, it’s up- or downregulation impaired FA protein composition and phosphorylation status, interfered with a proper spindle and chromosome segregation, disturbed the assembly and disassembly rate of FA, delayed cell adhesion, and compromised the plus-tip dynamics of MTs. In conclusion, our data suggest MCAK act as an important regulator for cell motility and migration by affecting the actin-MT cytoskeleton dynamics and the FA turnover, providing molecular mechanisms by which deregulated MCAK could promote malignant progression and metastasis of tumor cells.

scholarly journals RAB10 Interacts with ABCB4 and Regulates Its Intracellular Traffic

2021 ◽  
Vol 22 (13) ◽  
pp. 7087
Author(s):  
Amel Ben Saad ◽  
Virginie Vauthier ◽  
Martine Lapalus ◽  
Elodie Mareux ◽  
Evangéline Bennana ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Molecular Mechanisms ◽  
Significant Proportion ◽  
Deep Understanding ◽  
Small Gtpase ◽  
Membrane Expression ◽  
Intracellular Traffic ◽  
And Function ◽  
Cholestatic Diseases ◽  
Phosphatidylcholine Secretion

ABCB4 (ATP-binding cassette subfamily B member 4) is an ABC transporter expressed at the canalicular membrane of hepatocytes where it ensures phosphatidylcholine secretion into bile. Genetic variations of ABCB4 are associated with several rare cholestatic diseases. The available treatments are not efficient for a significant proportion of patients with ABCB4-related diseases and liver transplantation is often required. The development of novel therapies requires a deep understanding of the molecular mechanisms regulating ABCB4 expression, intracellular traffic, and function. Using an immunoprecipitation approach combined with mass spectrometry analyses, we have identified the small GTPase RAB10 as a novel molecular partner of ABCB4. Our results indicate that the overexpression of wild type RAB10 or its dominant-active mutant significantly increases the amount of ABCB4 at the plasma membrane expression and its phosphatidylcholine floppase function. Contrariwise, RAB10 silencing induces the intracellular retention of ABCB4 and then indirectly diminishes its secretory function. Taken together, our findings suggest that RAB10 regulates the plasma membrane targeting of ABCB4 and consequently its capacity to mediate phosphatidylcholine secretion.

scholarly journals Cell motility through plasma membrane blebbing

2008 ◽  
Vol 181 (6) ◽  
pp. 879-884 ◽  
Author(s):  
Oliver T. Fackler ◽  
Robert Grosse
Keyword(s):  
Plasma Membrane ◽  
Cell Motility ◽  
Molecular Mechanisms ◽  
Cell Movement ◽  
Core Component ◽  
Membrane Blebbing ◽  
Membrane Blebs ◽  
Bleb Formation ◽  
Guanosine Triphosphatase

Plasma membrane blebs are dynamic cytoskeleton-regulated cell protrusions that have been implicated in apoptosis, cytokinesis, and cell movement. Influencing Rho–guanosine triphosphatase activities and subsequent actomyosin dynamics appears to constitute a core component for bleb formation. In this paper, we discuss recent evidence in support of a central role of nonapoptotic membrane blebbing for cell migration and cancer cell invasion as well as advances in our understanding of the underlying molecular mechanisms. Based on these studies, we propose that in a physiological context, bleb-associated cell motility reflects a cell's response to reduced substratum adhesion. The importance of blebbing as a functional protrusion is underscored by the existence of multiple molecular mechanisms that govern actin-mediated bleb retraction.

Glia Maturation Factor-Gamma Mediates Human Monocytes Migration Through Regulating β1/β2-Integrin Recycling

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1027-1027
Author(s):  
Wulin Aerbajinai ◽  
Lunhua Liu ◽  
Chutima Kumkhaek ◽  
Kyung Chin ◽  
Griffin P. Rodgers
Keyword(s):  
Plasma Membrane ◽  
Molecular Mechanisms ◽  
Conflicts Of Interest ◽  
Inflammatory Cells ◽  
Effective Control ◽  
Glia Maturation Factor ◽  
Β2 Integrin ◽  
Maturation Factor ◽  
Early Endosomes ◽  
And Migration

Abstract Recruitment of monocytes is essential for effective control and clearance of invading pathogens by migrating to the sites of infection, but recruited monocytes also contribute to the pathogenesis of chronic inflammatory and degenerative diseases, such as rheumatoid arthritis, multiple sclerosis, atherosclerosis and cancer. Thus, understanding the mechanisms controlling monocytes migration within different environments is of paramount importance. Although it is clear that adhesion signaling via integrin receptors and the surrounding ECM play a significant role in regulating migration of monocytes to site of inflammation, the underlying cellular and molecular mechanisms responsible for these process is still not fully characterized. Defining the molecular circuits through which integrins regulate monocytes motility is therefore important for gaining a better understanding of monocytes function. Glia maturation factor gamma (GMFG), a novel ADF/cofilin superfamily protein that is predominantly expressed in inflammatory cells, has been implicated in regulating actin reorganization. We have previously demonstrated that GMFG plays a role in regulating neutrophil chemotaxis and migration. We now examine whether GMFG has similar effects on monocytes and the cellular mechanism for these effects by using small-interfering RNA to knockdown GMFG in human primary monocytes. Knockdown of endogenous GMFG results in significantly reduced (220.6 ± 9.4 to 89.0 ± 3.2, p<0.003) chemotactic migration toward SDF-1 and enhanced adhesion on fibronectin, VCAM-1 and ICAM-1 compared with control siRNA transfected cells. Flow cytometry analysis shows that knockdown of GMFG enhances the expression of β1-, β2−integrin on the cell surface compared with control cells. Confocal microscopy analysis exhibited that GMFG is colocalized with internalized β1-, β2-integrin in early endosomes in primary monocytes. However, an internalization assay shows that β1- and β2-integrin were internalized with similar kinetics during the initial uptake time points both in control or GMFG knockdown primary monocytes. These data demonstrated that internalization of β1- and β2-integrin was not impaired in GMFG knockdown cells, suggesting that GMFG regulates β integrins recycling. Antibody-based recycling assays showed that GMFG knockdown cells resulted in enhanced plasma membrane exocytosis of β1- and β2-integrin compared with control cells. Western blot analysis revealed that SDF-1 stimulated the phosphoryalation of FAK (Tyr397) is moderately (∼ 40%) increased in GMFG knockdown monocytes compared with control cells. These results suggest that impaired monocytes migrated toward SDF-1 stimulation in GMFG depletion monocytes is due to enhanced adhesion, which is caused by accelerated recycling of β1- and β2-integrin to the surface. Taken together, these results indicate that GMFG is required to maintain the proper expression levels of β1- and β2-integrin on the plasma membrane and is fundamental for integrin-mediated monocytes motility. Disclosures: No relevant conflicts of interest to declare.

scholarly journals α1AMP-Activated Protein Kinase Protects against Lipopolysaccharide-Induced Endothelial Barrier Disruption via Junctional Reinforcement and Activation of the p38 MAPK/HSP27 Pathway

2020 ◽  
Vol 21 (15) ◽  
pp. 5581
Author(s):  
Marine Angé ◽  
Diego Castanares-Zapatero ◽  
Julien De Poortere ◽  
Cécile Dufeys ◽  
Guillaume E. Courtoy ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Actin Cytoskeleton ◽  
P38 Mapk ◽  
Connexin 43 ◽  
Molecular Mechanisms ◽  
Small Gtpase ◽  
Endothelial Barrier ◽  
Barrier Disruption ◽  
Cellular Junctions

Vascular hyperpermeability is a determinant factor in the pathophysiology of sepsis. While, AMP-activated protein kinase (AMPK) is known to play a role in maintaining endothelial barrier function in this condition. Therefore, we investigated the underlying molecular mechanisms of this protective effect. α1AMPK expression and/or activity was modulated in human dermal microvascular endothelial cells using either α1AMPK-targeting small interfering RNA or the direct pharmacological AMPK activator 991, prior to lipopolysaccharide (LPS) treatment. Western blotting was used to analyze the expression and/or phosphorylation of proteins that compose cellular junctions (zonula occludens-1 (ZO-1), vascular endothelial cadherin (VE-Cad), connexin 43 (Cx43)) or that regulate actin cytoskeleton (p38 MAPK; heat shock protein 27 (HSP27)). Functional endothelial permeability was assessed by in vitro Transwell assays, and quantification of cellular junctions in the plasma membrane was assessed by immunofluorescence. Actin cytoskeleton remodeling was evaluated through actin fluorescent staining. We consequently demonstrate that α1AMPK deficiency is associated with reduced expression of CX43, ZO-1, and VE-Cad, and that the drastic loss of CX43 is likely responsible for the subsequent decreased expression and localization of ZO-1 and VE-Cad in the plasma membrane. Moreover, α1AMPK activation by 991 protects against LPS-induced endothelial barrier disruption by reinforcing cortical actin cytoskeleton. This is due to a mechanism that involves the phosphorylation of p38 MAPK and HSP27, which is nonetheless independent of the small GTPase Rac1. This results in a drastic decrease of LPS-induced hyperpermeability. We conclude that α1AMPK activators that are suitable for clinical use may provide a specific therapeutic intervention that limits sepsis-induced vascular leakage.

Wnt/beta-catenin and PI3K/Akt/mTOR Signaling Pathways in Glioblastoma: Two Main Targets for Drug Design: A Review

2020 ◽  
Vol 26 (15) ◽  
pp. 1729-1741 ◽  
Author(s):  
Seyed H. Shahcheraghi ◽  
Venant Tchokonte-Nana ◽  
Marzieh Lotfi ◽  
Malihe Lotfi ◽  
Ahmad Ghorbani ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Cellular Proliferation ◽  
Chemotherapy Resistance ◽  
Wnt Signaling Pathway ◽  
Therapeutic Interventions ◽  
Beta Catenin ◽  
Clinical Prognosis ◽  
Invasion And Migration ◽  
And Migration

: Glioblastoma (GBM) is the most common and malignant astrocytic glioma, accounting for about 90% of all brain tumors with poor prognosis. Despite recent advances in understanding molecular mechanisms of oncogenesis and the improved neuroimaging technologies, surgery, and adjuvant treatments, the clinical prognosis of patients with GBM remains persistently unfavorable. The signaling pathways and the regulation of growth factors of glioblastoma cells are very abnormal. The various signaling pathways have been suggested to be involved in cellular proliferation, invasion, and glioma metastasis. The Wnt signaling pathway with its pleiotropic functions in neurogenesis and stem cell proliferation is implicated in various human cancers, including glioma. In addition, the PI3K/Akt/mTOR pathway is closely related to growth, metabolism, survival, angiogenesis, autophagy, and chemotherapy resistance of GBM. Understanding the mechanisms of GBM’s invasion, represented by invasion and migration, is an important tool in designing effective therapeutic interventions. This review will investigate two main signaling pathways in GBM: PI3K/Akt/mTOR and Wnt/beta-catenin signaling pathways.

Effects and Mechanisms of Anlotinib and Dihydroartemisinin Combination Therapy in Ameliorating Malignant Biological Behavior of Gastric Cancer Cells

2020 ◽  
Vol 21 ◽  
Author(s):  
Qiong Luo ◽  
Suyun Zhang ◽  
Donghuan Zhang ◽  
Rui Feng ◽  
Nan Li ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cancer Cells ◽  
Molecular Mechanisms ◽  
Chorioallantoic Membrane ◽  
Cell Counting ◽  
Biological Behavior ◽  
Gastric Cancer Cells ◽  
Invasion And Migration ◽  
Apoptosis Related Protein ◽  
And Migration

Background: Gastric cancer(GC) is currently one of the major malignancies that threatens human lives and health. Anlotinib is a novel small-molecule that inhibits angiogenesis to exert anti-tumor effects. However, the function in gastric cancer is incompletely understood. Objective: The aim of the present study was to investigate the anti-tumor effects and molecular mechanisms of anlotinib combined with dihydroartemisinin (DHA) in SGC7901 gastric cancer cells. Method: Different concentrations of anlotinib and DHA were used to treat SGC7901 gastric cancer cells, after which cell proliferation was measured. Drug interactions of anlotinib and DHA were analyzed by the Chou-Talalay method with CompuSyn software. proliferation, apoptosis, invasion, migration, and angiogenesis were measured using the cell counting kit-8 (CCK8) assay, flow cytometry, Transwell invasion assays, scratch assays, and chicken chorioallantoic membrane (CAM) assays. proliferation-associated protein (Ki67), apoptosis-related protein (Bcl-2), and vascular endothelial growth factor A (VEGF-A) were quantified by Western bloting. Results: The combination of 2.5 μmol/L of anlotinib and 5 of μmol/L DHA was highly synergistic in inhibiting cell growth, significantly increased the apoptosis rate and suppressed obviously the invasion and migration capability and angiogenesis of gastric cancer cells. In addition, the expression levels of Ki67, Bcl-2, and VEGF-A, as well as angiogenesis, were significantly decreased in the Combination of drugs compared with in control and either drug alone. Conclusion: The combination of anlotinib and DHA showed synergistic antitumor activity, suggesting their potential in treating patients with gastric cancer.

scholarly journals Revising Endosomal Trafficking under Insulin Receptor Activation

2021 ◽  
Vol 22 (13) ◽  
pp. 6978
Author(s):  
Maria J. Iraburu ◽  
Tommy Garner ◽  
Cristina Montiel-Duarte
Keyword(s):  
Plasma Membrane ◽  
Tyrosine Kinase ◽  
Insulin Receptor ◽  
Molecular Mechanisms ◽  
Receptor Activation ◽  
Small Gtpases ◽  
Early Endosome ◽  
Tyrosine Kinase Receptors ◽  
Endosomal Trafficking ◽  
Cell Functions

The endocytosis of ligand-bound receptors and their eventual recycling to the plasma membrane (PM) are processes that have an influence on signalling activity and therefore on many cell functions, including migration and proliferation. Like other tyrosine kinase receptors (TKR), the insulin receptor (INSR) has been shown to be endocytosed by clathrin-dependent and -independent mechanisms. Once at the early endosome (EE), the sorting of the receptor, either to the late endosome (LE) for degradation or back to the PM through slow or fast recycling pathways, will determine the intensity and duration of insulin effects. Both the endocytic and the endosomic pathways are regulated by many proteins, the Arf and Rab families of small GTPases being some of the most relevant. Here, we argue for a specific role for the slow recycling route, whilst we review the main molecular mechanisms involved in INSR endocytosis, sorting and recycling, as well as their possible role in cell functions.

scholarly journals Circular RNA mmu_circ_0005019 inhibits fibrosis of cardiac fibroblasts and reverses electrical remodeling of cardiomyocytes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Na Wu ◽  
Chengying Li ◽  
Bin Xu ◽  
Ying Xiang ◽  
Xiaoyue Jia ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Cardiac Fibroblasts ◽  
Circular Rna ◽  
Protective Role ◽  
Luciferase Reporter ◽  
Loss Of Function ◽  
Candidate Target ◽  
Paired Control ◽  
Reporter Assays ◽  
And Migration

Abstract Background Circular RNA (circRNA) have been reported to play important roles in cardiovascular diseases including myocardial infarction and heart failure. However, the role of circRNA in atrial fibrillation (AF) has rarely been investigated. We recently found a circRNA hsa_circ_0099734 was significantly differentially expressed in the AF patients atrial tissues compared to paired control. We aim to investigate the functional role and molecular mechanisms of mmu_circ_0005019 which is the homologous circRNA in mice of hsa_circ_0099734 in AF. Methods In order to investigate the effect of mmu_circ_0005019 on the proliferation, migration, differentiation into myofibroblasts and expression of collagen of cardiac fibroblasts, and the effect of mmu_circ_0005019 on the apoptosis and expression of Ito, INA and SK3 of cardiomyocytes, gain- and loss-of-function of cell models were established in mice cardiac fibroblasts and HL-1 atrial myocytes. Dual-luciferase reporter assays and RIP were performed to verify the binding effects between mmu_circ_0005019 and its target microRNA (miRNA). Results In cardiac fibroblasts, mmu_circ_0005019 showed inhibitory effects on cell proliferation and migration. In cardiomyocytes, overexpression of mmu_circ_0005019 promoted Kcnd1, Scn5a and Kcnn3 expression. Knockdown of mmu_circ_0005019 inhibited the expression of Kcnd1, Kcnd3, Scn5a and Kcnn3. Mechanistically, mmu_circ_0005019 exerted biological functions by acting as a miR-499-5p sponge to regulate the expression of its target gene Kcnn3. Conclusions Our findings highlight mmu_circ_0005019 played a protective role in AF development and might serve as an attractive candidate target for AF treatment.

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